IG is a leftover from pre-DECOMPILE days, yeh. (Although you say it has problems with a DLG? I assumed it'd be more reliable than trying to decompile things.) Why on earth it's using the wrong IDS value, I don't know. It definitely worked at some point.
It says that IG is expecting a string but finds an integer - maybe WeiDU doesn't like S:String*D0Vtype anymore, or something. Try decompiling Trax.dlg with the current version of Virtue installed, and then traifying it. (don't ask me what on Earth I was doing or testing, since I cannot recall, honestly
)
In my tests, with DECOMPILE/COMPILE (after correcting the action.ids reference) I only get errors with BG1 leftovers, similar to those in the BCSes (Abela, Charle, Nobw8, Prism, Quinn, Silke.dlg).